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By G. M. Matheson

Mining in the Colorado Springs coal field took place from the 1880's to 1940's. The depth of mining in the coal field varied from about 10 meters to over 150 meters. Review of sequential historical aerial photographs from 1937 to 1960 indicated about 2400 chimney subsidence sinkholes had developed throughout the study area. Statistical analyses of the location and size of these sinkholes with respect to the time since mining, depth of mining, mined thickness and type of mining indicated definite trends in the time of occurrence, size, and location of these features. This data is valuable in the assessment of potential future subsidence in this and other areas of similar mining conditions.

Jan 1, 1985

By R. Mittler

Over 100 saprolite samples from Turkey Hill Gold Mine, Lumpkin County, Georgia, were analyzed (-80 mesh) for As, Au, and Sb. Maximum values are 16.2 ppm As, 7.9 ppm Au, and 29.1 ppm Sb. Results show trace element content of saprolite varies with topography: ridge top samples show a pronounced decrease in Au and Sb, and to a lesser degree in As, whereas, slope and valley samples have anomalous Au and Sb concentrations, with no discernable pattern for As. Statistical analysis shows strong correlation between Au and Sb and none between Au and As. This study will serve as a model for gold exploration in deeply weathered terrains with variable relief.

Jan 1, 1987

By R. L. Bleifuss

The object of this study was to evaluate the oxidized taconites of the western Mesabi iron range and to establish a correlation between the various basic taconite types and their concentratability. This study was made at the Mines Experiment Station of the University of Minnesota under the sponsorship of the Great Northern Railway Company. The initial work included a study of the original mineralogical and stratigraphic facies of the fresh taconite and traced the oxidation and leaching patterns developed during the conversion of this material to oxidized taconite. Subsequent studies have extended this work to include the semi- taconites and also the wash and heavy media ore types widely developed in the area. Each basic, original mineralogical facies or taconite type produces during alteration an equivalent secondary oxidized facies which has a unique mineralogical composition and texture. These control the concentratability of the oxidized taconites. Actually the influence of the original mineralogical composition of the iron formation extends even further and determines whether the most likely product of oxidation and leaching will be a wash ore or a heavy media ore and even to the direct shipping ores where the ratio of hematite to goethite is largely determined by the original taconite type.

Jan 1, 1964

By P. J. Lafforgue

In 1974- COGEMA (Compagnie Generale des Matieres Nucleaires) of France decided to exploit a uranium deposit discovered several years ago in a Permian formation of Southern France, near the town of Lodeve (Herault). The uranium occurs in black shales with high calcium carbonate content (7-10% CO2) and it was then necessary to use alkaline leaching. A fine grind (60-65% minue 270 mesh) was also necessary to obtain good' uranium recovery. A minimum of fresh water must be added to the alkaline system due to solution recycling. Filtration must be used because cake-washing requires less fresh water than countercurrent decantation.

Jan 1, 1982

By Michael Davis

In the fairly recent past, with a history of cheap and abundant energy, it has been possible to predict with reasonable confidence that world energy demand would continue to double about every 15 years. Those who attempted to forecast the role of nuclear energy in future electricity generation could also start with the fairly safe assumption that electricity demand would increase even faster : with a doubling in demand about every 10 years. To estimate the likely future world demand for uranium it was then necessary to introduce a number of other assumptions including the rate of penetration of nuclear energy, the timing and the specific fuel requirements. This series of assumptions naturally compounded the uncertainty, but, remarkably, usually led to future uranium demands being overestimated. Such a bias which has almost always been observed in predictions made over the past 20 years has increasingly made uranium producers sceptical when expected to match the forecast demand with increased production capacity and supporting reserves. This scepticism has, of course, been reinforced by the persistence so far of a buyers' market in uranium throughout the entire period of emergence of commercial nuclear electricity generation.

Jan 1, 1974

By William E. Bruce

Percussive drill calibration experiments performed by the Bureau of Mines on two drills are described. The use of a linear velocity transducer to determine piston velocity, blow frequency, and piston stroke length is discussed. Data are presented on the relationships between maximum work rate and feed air pressure. Penetration rates in nine rock types were measured for the same two drills. Physical properties of the nine rock types are presented in tabular and graphical form to show relationships between penetration rates and physical properties. Finally, conclusions are drawn as to the potential use of these data to predict percussive drilling rates.

Jan 1, 1970

By J. J. Reilly

The Vesta Mines of the Jones & Laughlin Steel Corporation operate in the Pittsburgh Seam in Washington County, Pennsylvania. This seam is overlain with a drawslate, 12" to 16" in thickness, which slimes readily when wet. Because of the need for a uniformly good quality metallurgical coal, the amount of reject, together with the top and particle sizes of the raw coal feed, is a serious problem at the Vesta Preparation Plant. The Preparation Plant operates two, seven and one-quarter hour shifts per day and processes 2,100 tons per hour of raw coal feed. The third shift is, used for planned maintenance of equipment. Since the water clarification equipment is so vital in insuring a uniform product, there is no alternative but that it be in operation at all times. To insure this continuous operation,. well-planned maintenance is a necessity. For years, Plant Management has kept performance records of the various units to determine the renewal dates of vital component parts, the length of wear, the various materials used in the manufacture of the equipment, and the labor cost for renewal. These records have been of inestimable help in planning an effective maintenance program to insure continuous operation of the various units.

Jan 1, 1959

By E. G. Williams

Underclays and shales are two natural resources associated with the coal measures. Underclays are widely used as the raw material for refractory, semi-refractory, and face bricks. Shales are useful for sewer pipe and lightweight aggregate. This study concentrates on the geologic controls over the properties of shales for use in the manufacture of lightweight aggregate, and the geologic controls over the properties of underclays for use in the manufacture of bloating ladle refractories. The industrial processes are similar in that both involve the trapping of a gas phase to cause bloating. They differ in that the bloating of lightweight aggregate occurs at lower temperatures (1000-1200°C) than ladle bricks (1350°-1470°C). Lightweight aggregate bloats during an initial rapid firing. Ladle bricks are manufactured by slow firing at 1100°C for up to 80 hours. Bloating occurs when these bricks are reheated to 1350°C . Bloating shales are those which expand twice or more times their original volume during fairly rapid firing. Commercial bloating is usually done by rotary kiln processing or sintering; in both cases the firing rate is much faster than the experimental rate (5/8°C/minute). Bloating results from the entrapment of gasses which are evolved during firing. The material must have adequate viscosity to trap gas bubbles throughout the temperature range of bloating. The finished product contains a high percentage of closed pores with a bulk density between 35-75 pounds per cubic foot. Expanded shale finds its most important use as a substitute for heavy concrete aggregate (crushed stone, sand and gravel) where low bulk density is desired property. The extent of bloating in lightweight aggregate is a function of the mineralogy and chemistry of the shale. Figure 1 shows a corner of the three phase diagram, kaolinite-quartz-(illite and chlorite). Several areas on the diagram are outlined which contain predominantly marine shales, fresh and brackish water shales, and underclays. Each sample was rapid fired and the resulting expansion was plotted on the phase diagram.

Jan 1, 1973

By D. G. Feuerbacher

Maximizing production of oil from sandstone petroleum reservoirs is aided by use of non-damaging drilling and workover/completion fluids. Various tests, such as X-ray diffraction, scanning electron microsccpy, petrographic microscopy, porosity and permeability are conducted on core samples. Several fluids are selected, on the basis of these results, for return permeability tests. A report is then written giving the results of all tests, potential reservoir problems, and recommended practices for exploiting the reservoir.

Jan 1, 1983

By German Zambrana

The solution of the problem of beneficiation of cassiterite from its primary ore deposits is of fundamental importance to Bolivia. The process today involves a gravimetric treatment of the ore followed by sulphide flotation. During the last year, a cassiterite flotation stage has been added in several plants to treat the slime tailings. Although cassiterite flotation is already economical for the slime tailings and the mechanism of the process are understood, it is felt that further research could improve the results. In the past, considerable amount of research and test ark has been performed to select appropriate collectors to improve recovery, to increa¬se the grade of tin in the concentrate, to minimize the effect of metallic ions like Ca+2, Fe+2 and Fe+3 which prevent flotation, and to increase the pH of the pulp which now it can not be higher than 3.0. It has been reported that the halogen salts (1) like NaCl exhibit special surface affinity for cassiterite but none for quartz. These effect seems to be favourable for the selective flotation of cassiterite from silica minerals. In view of these preliminary results it was decided to follow the research accordingly: OBJECTIVES The objectives of the present investigation are: 1. 0 evaluate the influence of NaCl salts in quartz and cassiterite flotation.

Jan 1, 1971

By Peter L. Comanor

At Getchell, Nevada a thousand tons per day mill for extracting gold from an ore containing orpiment and realgar was operated several years until early 1967. A cyanide process with a roaster was used in the processing of the ore. Mill wastes were contained in tailings ponds, in which the concentration of arsenic, currently, is one per cent or higher, Studies were conducted determining the effect of the tailing wastes on the Upper Sonoran vegetation of the area. Grid and line-intercept techniques were employed to obtain botanical informatics of the area surrounding the tailings ponds. Data of the per cent ground cover, species frequency, and plant vitality as a function of distance from the tailings ponds was collected. The data was compared to other botanical data collected from a control site outside the influence of the tailings ponds. In an attempt to isolate naturally occurring factors for varying plant communities from hose induced by factors derived from the close proximity of the tailings, soil cores were taken along the line-intercepts at intervals of 30 meters. The cores were analyzed for several compounds and elements needed for growth, or known to inhibit growth. Specific physical parameters of the soil samples were also taken. The paper describes the impact made by mill wastes containing large amounts of arsenic on the Upper Sonoran vegetation of the Getchell region. Described in detail are the techniques used to make the correlations between the plant communities and the influences of mill wastes.

Jan 1, 1974

By C. D. Harrison

This paper presents the results of 18 high-G centrifuge tests performed at the Electric Power Research Institute's Coal Cleaning Test Facility in January 1985. These tests, using -28 mesh (0.6mm) froth flotation product, show that the high-G, solid-bowl centrifuge can produce clean-coal moistures of less than 12 percent at solids recovery rates exceeding 98 percent. The high-G centrifuge achieved these low moistures by applying centrifugal forces up to 2,000 times gravity. Because these forces are two to three times the forces used in a screen-bowl centrifuge, the high-G centrifuge can use a solid bowl and still produce a low-moisture product. The solid bowl captures ultrafines that would pass through a screen bowl, and thus obtains higher recovery rates than a screen-bowl centrifuge.

Jan 1, 1985

By Vas P. Srinivasa

This paper examines the role of the heavy media separator in the mineral industry. Procedures used in selecting the separating vessel, developing the process flowsheet, and designing a heavy media circuit are discussed. For comparative purposes, the capital investment and operating costs of different types of operation are included.

Jan 1, 1981

By E. M. Schern

The Morenci/Metcalf porphyry copper mining operation, located in southeastern Arizona, currently processes approximately 100,000 tons of ore per day and has copper ore reserves estimated to be in excess of one billion tons. Functional groups within the Geology Depart¬ment (currently staffed with six professional and two support personnel) include mine geology, project geology, and hydrogeology. The primary task of mine geologists is daily preblast bench face mapping with grade and mill amenability estimates. Auxiliary duties include detailed in-pit metal distribution evaluation, mineragraphic work and flux quarry geology. Project geologists conduct explora¬tion and preliminary development projects both within and outside the Morenci district and provide support to ore reserve block modeling and geotechnical work performed by the Morenci mine engineering group. Hydrogeologists handle exploration for and development of groundwater' resources and groundwater flow modeling, mine dump leach solution penetration and recovery evaluation, and tailing dam water reclamation.

Jan 1, 1983

By Young C. Kim

In the past, underground coal mine planning has traditionally focused on the mine design n aspects concerning safety and efficiency in the quest to produce low cost coal. Very little attention has been given to coal quality control aspects of mine planning at most of the underground coal mines within the U.S. With the enactment of the clean air act of 1970, the generally high sulfur content of coal has become a major concern for the coal-fired power plants in the east. Similarly, the ash and the BTU contents of coal are of equal importance from boiler efficiency standpoint. Thus, the time has come when the coal mine planning must incorporate the coal quality control aspects as well as the traditional safety and efficiency aspects.

Jan 1, 1983

By M. D. Lawton

Anglo-Rouyn Mines Limited, managed by Rio Algom Mines Limited is a subsidiary of the British-based Rio Tinto-Zinc Corporation Limited. This mining operation is situated in Northern Saskatchewan, 250 miles north of Saskatoon and represents the first base-metal mine of any importance served by this relatively new mining province. The outcrop of Copper-bearing Chalcopyrite was first discovered by prospectors in 1915, but was not mined until 1965 due to the absence of any form of road into the area prior to this latter date. The mine, mill and concentrator were designed to handle 900 tons per day of comparatively hard, abrasive ore containing chalcopyrite with traces of gold and silver. The flow sheet, Figure 1, is, we believe, elementary, designed with low cost in mind and utilises much old equipment from closed¬-down mines. Due to some difficulty in attaining the designed grinding capacity, changes were made in the crusher circuit. This, unfortunately, lowered the crushing rate too much. A series of changes have taken place to re-establish the original crusher capacity of better than 100 tons per hour. In the quest for a better recovery certain modifications have been tested in the concentrator circuit. These steps are discussed in minor detail.

Jan 1, 1970

By Lorraine Brandt Yde

This paper describes development of a cost report that is descriptive, logically oriented, and concise. Since the costs involved relate to mining, this reporting technique could help bridge any possible communications gap between "mining men" and computer personnel, at the same time giving the computer-oriented mining individual information to assist him in his job performance. As computers become entrenched in the mining world, meaningful report assimilation becomes a major task. No one should be more capable of defining required results than the man requesting a report. If he is able to clearly state his needs and has researched his problem, it will be reflected in the computer output. During 1970, The Anaconda Company's Berkeley Pit Operation, at Butte, Montana, received many different computer-generated equipment cost reports. Up to thirty-six different components for each type (class) of pit equipment contributed cost data to the Berkeley Pit cost system files for both operating and repairs during current month, year-to-date and accumulation-to-date time periods. This reporting approach was taken to facilitate analyzing this voluminous data. SUMMARY A Major Component Cost Analysis (Exhibits 6-A thru 6-C) developed by arranging the top ten operating and repair percentages (component cost divided by total cost) in descending order, and then accumulating these percentages to a possible one-hundred percent. While tabulating the operating and repair cost percentages by equipment unit number in the current month, year-to-date and accumulation-to-date time periods, a frequency chart is constructed for each equipment

Jan 1, 1971

By Reul A. Dejú

The mineral olivine has been the subject of continued research by various authors. Paik (1967) conducted infrared and flotation studies of the adsorption of sodium alkyl benzene sulfonates on olivine. These studies are of interest from two points of view. First, in the metallurgical field it is of interest to understand the mechanism of silicate flotation using sulfonate collectors and second to a hydrologist studying the pollution of surface or subsurface waters it is of interest to study the reactions taking place when water plus sulfonates encounter a porous (silicate) medium. On the basis of Paik's study he was able to postulate a possible mechanism for the attachment of RSO3 (sulfonate radical) to the olivine surface. Parks (1969) has been studying the important influence of the structure of a silicate such as olivine on its dissolution mechanism and its related surface charge. Also Luce, a student of Parks (1964, 1965) has been studying the kinetics of dissolution of olivine using the techniques of direct solution analysis and infrared analysis. Certainly a classic in the study of silicate dissolution is the work of Murata (1940) on the reaction of orthosilicates (olivine in particular) with strong acid solutions. Many authors (Dejú and Bhappu, 1966. 1967. 1968, Dejú, 1969; Rhoades and Krueger. 1968, and Faust and blunter, 1967) have reported studies of the behavior of silicates immersed in water (especially orthosilicates) and have found that there is an exchange of cations from the silicate surface for H+ from the water. Studies by Dejú and Bhappu have also included the system olivine-water-amine.

Jan 1, 1971

By Sam H. Patterson

Australia has led the world in bauxite production since 1976, and only the Republic of Guinea has larger bauxite resources. India has a small integrated aluminum industry, and deposits containing more than 1 Gt (billion metric tons) of bauxite were discovered in the 1970's. The Peoples Republic of China has large bauxite resources scattered in several regions, but it is a monohydrate type that is difficult to process for aluminum. Indonesia and Malaysia both have long histories of bauxite mining, and both have limited resources of high-grade bauxite. Districts containing bauxite resources in the 10 Mt to 150 Mt (million metric tons) range are scattered in countries along the eastern rim of the Pacific Ocean, on islands in this ocean, and on the western and northern rims of the Indian Ocean.

Jan 1, 1982

It was shown previously that chalcopyrite could be floated without using a collector when the ore samples were treated with small amounts of sodium sulfide (Na2S). The role of this reducing agent was considered to be one of a cleaning agent to remove the hydrophilic surface oxidation products. It was later found, however, that the collectorless flotation could be obtained only under slightly oxidizing conditions. This might suggest that collectorless flotation is not due to the clean surface but to the elemental sulfur which may be present as an incipient oxidation product. Therefore, a search for the presence of elemental sulfur has been made by means of ESCA, mass spectrometry, and solvent extraction followed by W spectrophotometric analysis. On the basis of these results, the mechanisms of collectorless flotation are discussed.

Jan 1, 1983